CO2 levels rise more than expected

CO2 levels rise more than expected

Levels of carbon dioxide in the atmosphere have grown 35% more quickly than expected since 2000 because of inefficiency in fossil fuel use and the weakening of natural "carbon sinks", scientists warned.

Published 22nd October 2007

Increasing use of coal-fired power stations and a lack of technological improvements has led to a 17% increase of CO2 above expected levels, researchers at the University of East Anglia (UEA) said.

There has also been a decrease in the ability of land and oceans to absorb carbon dioxide, with the decline in efficiency of these natural sinks accounting for increases 18% above anticipated levels since 2000.

Over half the decline of the carbon sink efficiency is the result of intensifying winds in Antarctica's Southern Ocean disrupting the sea's ability to store carbon, the scientists from UEA, the British Antarctic Survey and the Global Carbon Project said.

The latest warning on rising CO2 levels, and its implications for climate change, is being published in the journal Proceedings of the National Academy of Sciences (PNAS). It comes just days after other researchers at UEA revealed that measurements of the north Atlantic from the mid-1990s to 2005 showed the level of carbon dioxide in its waters reduced by about half over the decade.

The new study's author Dr Corinne Le Quere, of UEA and the British Antarctic Survey, said winds were intensifying in the Southern Ocean because of climate change and depletion of the ozone layer.

The stronger winds were causing more "mixing" of the waters, bringing carbon up from the deep seas where it was stored and raising the carbon concentration of the surface water, which allowed less CO2 to dissolve into the ocean from the atmosphere. A decrease in fossil fuel efficiency is also speeding up the increase in atmospheric carbon dioxide levels, she said.

"What happened for 30 years is that we became more efficient in producing wealth from our emissions, but that has stalled since 2000. There's a slow change from oil and gas to coal which is more CO2 intensive. As developing countries grow so does their use of energy and coal is easier to access and cheaper.

"Developed countries have not been providing massive investment in technology to counteract that. We had anticipated that the growth in CO2 would follow the world economy but we had not anticipated that we would not be as efficient as we were being and the sinks would not respond," Dr Le Quere said.

And she warned: "The decline in global sink efficiency suggests that stabilisation of atmospheric CO2 is even more difficult to achieve than previously thought."